From: daniel.lezcano@linaro•org (Daniel Lezcano)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 1/2] time: Serialize calls to 'clockevents_update_freq' in the timing core
Date: Thu, 12 Dec 2013 13:07:45 +0100 [thread overview]
Message-ID: <52A9A711.1040002@linaro.org> (raw)
In-Reply-To: <ba4dce4a-1332-4fd8-80de-41347bb5b7b2@TX2EHSMHS005.ehs.local>
On 12/11/2013 09:09 PM, S?ren Brinkmann wrote:
> Hi Daniel,
>
> On Wed, Dec 11, 2013 at 03:32:57PM +0100, Daniel Lezcano wrote:
>> On 12/10/2013 01:34 AM, Soren Brinkmann wrote:
>>> From: Thomas Gleixner <tglx@linutronix•de>
>>>
>>> We can identify the broadcast device in the core and serialize all
>>> callers including interrupts on a different CPU against the update.
>>> Also, disabling interrupts is moved into the core allowing callers to
>>> leave interrutps enabled when calling clockevents_update_freq().
>>>
>>> Cc: Thomas Gleixner <tglx@linutronix•de>
>>> Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx•com>
>>> ---
>>> kernel/time/clockevents.c | 29 ++++++++++++++++++++++-------
>>> kernel/time/tick-broadcast.c | 25 +++++++++++++++++++------
>>> kernel/time/tick-internal.h | 4 ++++
>>> 3 files changed, 45 insertions(+), 13 deletions(-)
>>>
>>> diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
>>> index 086ad6043bcb..641d91003a45 100644
>>> --- a/kernel/time/clockevents.c
>>> +++ b/kernel/time/clockevents.c
>>> @@ -439,6 +439,16 @@ void clockevents_config_and_register(struct clock_event_device *dev,
>>> }
>>> EXPORT_SYMBOL_GPL(clockevents_config_and_register);
>>>
>>> +int __clockevents_update_freq(struct clock_event_device *dev, u32 freq)
>>> +{
>>> + clockevents_config(dev, freq);
>>> +
>>> + if (dev->mode != CLOCK_EVT_MODE_ONESHOT)
>>> + return 0;
>>> +
>>> + return clockevents_program_event(dev, dev->next_event, false);
>>> +}
>>> +
>>
>> ./arch/arm/kernel/smp_twd.c should be modified to call
>> __clockevents_update_freq instead of clockevents_update_freq, no ?
>
> IIUC, the __-version is only for timer core internal usage and not an
> exported interface. Doesn't the non-__ version work for the twd?
> I don't see issues on my Zynq platform with these patches.
I don't think there is an issue but if we can rid of the extra code
added in clockevents_update_freq with this patch for twd, it would make
sense. The __-version means the function is lockless and there is a
function without '__' in the name with the lock.
> Another side note regarding the twd: Shouldn't we set the
> CLOCK_EVT_FEAT_PERCPU flag we introduced recently for that timer?
Yes.
There will be some fun with the patchset http://lwn.net/Articles/566270/
where the local timer could be used as a broadcast timer.
--
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next prev parent reply other threads:[~2013-12-12 12:07 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-27 1:04 [PATCH v2 0/9] arm: zynq: Add support for cpufreq Soren Brinkmann
2013-11-27 1:04 ` [PATCH v2 1/9] arm: dt: zynq: Remove 'clock-ranges' from TTC nodes Soren Brinkmann
2013-12-12 8:53 ` Michal Simek
2013-12-12 17:01 ` Sören Brinkmann
2013-12-12 19:07 ` Michal Simek
2013-11-27 1:04 ` [PATCH v2 2/9] arm: dt: zynq: Add 'cpus' node Soren Brinkmann
2013-11-27 1:04 ` [PATCH v2 3/9] clocksource/cadence_ttc: Store timer frequency in driver data Soren Brinkmann
2013-12-17 19:21 ` Sören Brinkmann
2013-12-18 14:53 ` Daniel Lezcano
2013-12-18 16:47 ` Sören Brinkmann
2013-12-18 21:58 ` Daniel Lezcano
2013-12-19 18:32 ` Sören Brinkmann
2013-12-19 20:53 ` Daniel Lezcano
2013-12-19 21:23 ` Sören Brinkmann
2013-12-19 21:39 ` Daniel Lezcano
2013-11-27 1:04 ` [PATCH v2 4/9] clocksource/cadence_ttc: Use enable/disable_irq Soren Brinkmann
2013-11-28 11:55 ` Daniel Lezcano
2013-11-28 14:18 ` Thomas Gleixner
2013-11-28 18:36 ` Sören Brinkmann
2013-11-28 19:07 ` Thomas Gleixner
2013-12-06 22:47 ` Sören Brinkmann
2013-12-07 10:56 ` Thomas Gleixner
2013-12-10 0:34 ` [PATCH 0/2] clockevents Soren Brinkmann
2013-12-10 0:34 ` [PATCH 1/2] time: Serialize calls to 'clockevents_update_freq' in the timing core Soren Brinkmann
2013-12-11 14:32 ` Daniel Lezcano
2013-12-11 20:09 ` Sören Brinkmann
2013-12-12 12:07 ` Daniel Lezcano [this message]
2013-12-10 0:34 ` [PATCH 2/2] time: clockevents: Adjust timer interval when frequency changes Soren Brinkmann
2013-11-27 1:04 ` [PATCH v2 5/9] clocksource/cadence_ttc: Adjust interval in clock notifier Soren Brinkmann
2013-12-12 12:15 ` Daniel Lezcano
2013-12-12 18:44 ` Sören Brinkmann
2013-11-27 1:04 ` [PATCH v2 6/9] clocksource/cadence_ttc: Overhaul clocksource frequency adjustment Soren Brinkmann
2013-11-27 1:04 ` [PATCH v2 7/9] clocksource/cadence_ttc: Use only one counter Soren Brinkmann
2013-11-27 1:04 ` [PATCH v2 8/9] arm: zynq: Don't use arm_global_timer with cpufreq Soren Brinkmann
2013-11-27 1:04 ` [PATCH v2 9/9] arm: zynq: Add support for cpufreq Soren Brinkmann
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